Effects of Seeding Date and Population on Water-Use Efficiency and Safflower Yield1
- J. Alessi,
- J. F. Power and
- D. C. Zimmerman2
Oilseed crop production has increased greatly in the Northern Plains in recent years. Cultural practices to optimize oilseed production were studied for 4 years (1974–1977) to obtain information on safflower (Curthamus tinctoris L.) seed yield, oil concentration, and wateruse efficiency as affected by seeding date and plant population. Safflower was seeded on previously cropped or fallow land on three dates: early (16 May), midseason (6 June), or late (25 June) on Temvik silt loam (Typic Huploborolls). Soil water depletion by safflower was generally confined to the upper 150-cm soil depth. Average water use by safflower seeded in mid-May was greater by 4 and 8 cm than that used by the midseason and late seeding, respectively, and was unaffected by population. Significant positive correlations (r = 0.78) were obtained between oil concentration and degree days for the period after flowering. Correlation coefficients showed that 79% of the total variation in oil concentration was accounted for by variation in water use and temperature. Average water-use efficiency for mid-May, early June, and late June seeding was 34, 33, and 15 kg seed/cm water used, respectively. Seed and oil yields were highest for early and lowest for late seeding. In all years, seeding date affected seed yield and oil concentration. Population affected seed and oil yield in 1976. The results showed that safflower grown under dryland conditions in the Northern Plains should be seeded not later than mid-May. Previous research in North Dakota showed that for best results safflower should be planted between 20 April and 10 May.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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